The present invention relates to magnetic tape cassettes, and more particularly to an improved video tape cassette with a slide type brake member which is used to stop the rotation of the tape reels of the cassette.
In a conventional video tape cassette, the periphery of one of the two flanges of each of a pair of tape reels on which the magnetic tape is wound is formed with gear teeth, and the pawls of a slide type brake member are engaged therewith to prevent the tape reels from rotating when the cassette is not in use.
The configuration of the above-described slide type brake member is shown in FIG. 1. The brake member 1 has a recess 4 in the bottom of its body into which a release bar 14 (described below) of the recording and reproducing device is inserted, and a pair of pawls 5 on the front 2 of the body. The brake member 1 is arranged in the cassette with the recess 4 confronting a release bar inserting hole 10 in the lower half 7 of the cassette. The brake member 1 is urged towards a tape reel 11 by a spring 6 inserted between the brake member 1 and the wall 8 of the cassette, as shown in FIG. 2.
The periphery of one of the flanges 12 of the tape reel 11 is formed into a gear 13. When the cassette is not in use, the pawls 5 of the brake member 1 are engaged with the gear 13 by the elastic force of the spring 6 so as to prevent the tape from being unintentionally unwound. When the cassette is used, the tapered end of the release bar 14 is inserted through the release bar inserting hole 10 into the recess 4. Upon insertion of the release bar, the brake member 1 is slid away from the tape reel 11, being guided to move only in the direction of the arrow A, as a result of which the pawls 5 are disengaged from the gear 13.
However, the brake member 1 is liable to move unexpectedly during the assembly of the cassette; for instance, it may spring out of the lower half 7 due to the elastic force of the spring member 6. Accordingly, it is difficult to control the position of the brake member 1 until the latter is covered by the upper half 9, which lowers the efficiency of the cassette assembly operation.